Based on the possibility of PBH binaries detection at high redshift, we can directly observe the signals from the PBHs. This can help us build an early universe model. The mass function of PBHs can be obtained from the chirp mass of gravitational wave in the rest frame and gives clues to the inflation potential [1]}. The abundance distribution of PBHs can be obtained from the position distribution of gravitational wave events, which gives hint for inflation model with position properties, such as the initial clustering of PBHs from multi-stream inflation [2]}. The fraction of PBHs in the dark matter can be constrained by the high redshift gravitational wave event rate, which can tell us the potential dark matter candidates.
